Liquid cooler assembly

ABSTRACT

A compact oil cooling assembly suitable for a vehicle-mounted air compressor. Two oil cooling cores are operatively joined with a cooling fan by means of a shroud so that air flow generated by the fan passes serially through the cores for counter current flow cooling of the oil. The fan is disposed at one end of the shroud in a plane substantially perpendicular to the plane of the cooling cores at the other end of the shroud.

ilnited States Patent Potter et al.

[ Sept. 12, 1972 LIQUID COOLER ASSEMBLY Inventors: Olin E. Potter, Wilbraham; Biagio J. Tomasi, South Hadley Falls, both of Mass.

Worthington Compressor and Engine International Division of Worthington Corporation, a Division of Worthington Corporation, Holyoke, Mass.

Filed: Aug. 21, 1970 Appl. No.: 65,905

Related US. Application Data Continuation of Ser. No. 809,187, March 21, 1969, Pat. No. 3,588,288.

Assignee:

US. Cl. ..165/35, 165/43, 62/196, 62/243 Int. Cl. ..G25d 23/00 Field of Search ..165/35, 43, 44; 62/196, 268, 62/270, 198, 199, 192; 251/118; 417/234 [56] References Cited UNITED STATES PATENTS 3,300,619 l/ 1967 Nilssen ..165/43 X 3,494,413 2/1970 Dixon ..165/43 3,171,474 3/1965 Roane ..165/43 3,059,449 10/1962 Dilliner ..165/43 X Primary Examiner-Frederick L. Matteson Assistant ExaminerTheophil W. Streule Att0rneyFishman and Van Kirk [5 7] ABSTRACT A compact oil cooling assembly suitable for a vehiclemounted air compressor. Two oil cooling cores are operatively joined with a cooling fan by means of a shroud so that air flow generated by the fan passes serially through the cores for counter current flow cooling of the oil. The fan is disposed at one end of the shroud in a plane substantially perpendicular to the plane of the cooling cores at the other end of the shroud.

4 Claims, 7 Drawing Figures PATENTEDSEP 12 I972 SHEET 1 UF 2 INVENTORS m M r/ M POTTER J". TOMASI OLIN E BIAGIO PATENTEDSEP 12 I972 SHEET 2 OF 2 OLIN E.POTTER BIAGIO JITOMASI INVENTORS LIQUID COOLER ASSEMBLY CROSS REFERENCES TO RELATED APPLICATIONS:

This application is a continuation of US. Pat. application Ser. No. 809,187, filed Mar. 21, 1969 now U.S. Pat. No. 3,588,288 issued June 28, 1971.

BACKGROUND OF THE INVENTION:

1. Field of the Invention This invention relates to a compressor assembly in which the assembly structure is modified to be attached to some part of a vehicle, wherein the actuation of the compressor assembly is efiected through direct drive from the vehicle engine.

2. Description of the Prior Art Compressor systems have often been mounted on motor vehicles and driven by the vehicle engine. However, these vehicle mounted compressor systems have presented problems which have reduced the usefulness of the vehicle or the compressor or both. Many of these problems relate to the cooling system for the compressor. A separate compressor cooling system is preferable to a dual purpose cooling system which cools both the vehicle engine and the compressor.

Such dual purpose cooling systems have proven to be relatively inefficient because of the several compromises which must be made in the design of the system to provide the extra cooling capacity to cool the compressor in addition to the vehicle engine.

An example of such a compromise is shown in US. Pat. No. 1,255,632 issued to L. Poccia on Feb. 5 1918 in which a separate radiator member 41 for cooling compressor 30 is mounted and disposed behind radiator 13 for the vehicle engine 11. However, the fan 14, disposed between the two cores, of the engine radiator must be oversized so that enough air will be drawn through radiator cores 13 to cool the engine without unduly raising the temperature of the cooling air, since the temperature of the air after passing through engine radiator 13 must be low enough and the quantity of air great enough to affect the required heat transfer to cool the compressor when the air subsequently passes through auxiliary radiator 41.

Separate cooling systems for a vehicle mounted compressor include a separate radiator, fan and means to drive the fan. This equipment is usually bulky and complex and therefore prone to failure. Additionally, the mounting requirements to obtain efficient performance of the radiator and the fan drive often make it necessary to sacrifice valuable working space in the vehicle.

Accordingly, it is an object of the present invention to provide an improved vehicle mounted compressor assembly having a separate cooling system for the compressor.

Yet another object of the present invention is to provide an improved vehicle mounted compressor assembly having a separate cooling system for the compressor, which cooling system is driven through the compressor.

Still another object of the present invention is to provide an improved vehicle mounted compressor system which can be installed in a standard vehicle truck frame without excessive modification of the truck frame.

Yet another object of the present invention is to provide an improved vehicle mounted compressor assembly which can be mounted on the frame of a standard truck without using any of the available space above the truck chassis.

Still another object of the present invention is to provide a cooling system for a vehicle mounted compressor assembly having cooling cores arranged to provide counter current flow of the coolant therethrough.

Yet another object of the present invention is to provide an oil cooling assembly for a truck mounted compressor in which the fan for the oil cooling assembly rotates in a horizontal plane to produce minimum obstruction in the working area of the truck frame.

Still another object of the present invention is to provide a cooling assembly for a truck mounted compressor system with the cooling assembly having a horizontally disposed fan means driven through the compressor, which fan means can effect a horizontal flow of cooling air through the cooling cores.

Yet another object of the present invention is to provide an improved air receiver-oil separator tank for a vehicle mounted compressor system which receives an air oil mixture from the compressor discharge and separates the oil from the compressed air and separately stores the oil and the compressed air.

Still a further object of the present invention is to provide an air receiver-oil separator tank of reduced volume suitable for a vehicle mounted compressor system.

Yet another object of the present invention is an air oil separating and storage tank for a vehicle mounted compressor system in which the air oil separating element is disposed at least partially below the oil level in the tank.

SUMMARY OF THE INVENTION:

The present invention sets forth a vehicle mounted compressor system having a double ended rotarytype compressor and a separate cooling system for the compressor mounted on the vehicle frame. The vehicle engine provides power for both the rotary type compressor and the compressor cooling system by a series of drive shafts from the engine to the compressor and then from the compressor to the compressor cooling system. The components of the compressor system are designed to use a minimum of the normally usable space in vehicles. The oil and compressed air from the compressor discharge are separated and stored in a single horizontally disposed tank. The cooling system fan rotates in a horizontal plane to conserve space while the cooling cores are in a vertical plane to function at maximum efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1 is a schematic in plan view of the compressor system mounted on a truck frame.

FIG. 2 is a side view of FIG. 1.

FIG. 3 is a side view in section of the oil cooling assembly.

FIG. 4 is a rear end view of the oil cooling assembly.

FIG. 5 is a side view in section of the receiverdemister tank assembly in the compressor system.

FIG. 6 is a rear end view partly in section of FIG. 5.

FIG. 7 is a schematic representation of the flow path through the cooling unit.

DESCRIPTION OF THE PREFERRED EMBODIMENT:

FIGS. 1 and 2 show in phantom lines a standard industrial truck generally indicated at having a commonly available ladder type truck frame 12, a standard rear wheel assembly 14, the usual drivers compartment and running boards 16 and front wheel assembly 17. The engine of the truck 18 has a power take-off connection 20 which drives a rotary compressor 22 by means of a commonly known automotive type drive shaft assembly consisting of a splined drive shaft 28 having an externally splined section 27 axially slidably engaged with an internally splined hollow tubular section 29, the drive shaft 28 being connected at one end to the power take-off connection 20 by universal joint 26, and at the other end connected to the rotor shaft 32 of compressor 22 by a power receiving universal joint 30. The compressor 22 can be attached to the side rail 24 by any convenient method of attachment as for example by the use of a suitable bracket or fastening strap, not shown. The compressor rotor shaft 32 extends through the compressor housing 34 and drives the compressor cooler assembly generally indicated at 36 through a second automotive drive assembly consisting of a splined drive shaft 40 connected at one end to a right angle gear box 44 which provides power for the compressor cooler assembly.

The oil cooler assembly 36 is mounted from a cross brace 46 connected at each end to the side rails 24 of the truck ladder frame 12. The cooler assembly consists of series-connected first and second cooling cores 4% and 50 respectively, and a horizontally disposed fan 54 driven by shaft 56 extending from right angle gear box 44. A shroud member 52 is disposed about the first and second cooling cores and the fan 54, with the fan rotating in a plane slightly below the bottom 53 of the shroud the shape of the shroud 52 and the positioning of the fan 54 with respect to the shroud cause the fan when operating to draw air through the first and second cooling cores and exhaust the air downwardly towards the ground and radially outward. A shield 58 for the fan protects against accidental injury from the fan blades 54.

The compressor 22 has an inlet 64 and a discharge outlet 66 which is connected by suitable conduit means, designated by dashed lines 68, to the inlet 72 of an air receiver-oil separator tank 70. As shown in FIG. 5 and 6 the air receiver-oil separator tank 70 consists of an outer housing 78 with the inlet 72 mounted in the upper portion thereof, a compressed air discharge outlet 74 in the removable cover 36 and an oil outlet 76 in the bottom of the outer housing. An oil filler neck (not shown) attaches to opening 80 at the end of the housing and an oil level gauge 82 is located in the side of the housing to indicate the oil level 110 in the tank. The majority of the oil in the compressor discharge is separated from the compressed air upon entry through inlet 72 into the outer housing and falls to the bottom of the outer housing usually rising to the level 110 as shown in FIG. 5. A closed oil tight chamber 84 partially submerged in the oil within the outer housing is formed from a cylindrical member 85, closed at one end by a wall 87 and with aflange portion 89 at the other end, which flange is secured between the end cover 86 for the outer housing 78 and a bolting flange 88 on the outer housing 78 to which the end cover is fastened by a plurality of bolts 90. An air-oil separating element 92 is mounted within oil tight chamber 84 by means of a mounting rod 94 extending from an anchoring member 95 axially through the separating element and secured by mounting bolt 96 which presses against retaining member 98. The air-oil separating element includes a first cylindrical section generally indicated at 99 having perforated inner and outer walls 101 and 103 respectively enclosing a filtering material 105. A second cylindrical section generally indicated at 107 contains a plurality of discs of filtering material generally indicated at 109 disposed perpendicularly to the axis of the air oil separating element 92.

An opening in the top of oil tight chamber 84 allows compressed gas from the compressor discharge in outer housing 78 to enter the closed oil tight chamber and then pass through the air-oil separator element 92 wherein any oil remaining in the compressed gas will be separated out. The separated oil falls to the bottom section 102 of the oil tight chamber where it is drawn off by means of a siphon tube 104 which extends from the bottom section 102 of the oil tight chamber through opening 100 and out an opening 106 in the outer housing 78. The oil then passes by means of conduit 108 to an area of lower pressure to be more fully explained below.

A conduit shown as a dotted line 112 connects oil outlet 76 of air receiver-oil separator tank 70 to the inlet of a T-fitting 114 having one outlet connected to the inlet 116 of the first cooling core 48 and the second outlet connected by conduit 118 to a thermostatic valve 120 whose function will be explained later. As seen in FIGS. 3, 4 and 7 the oil entering inlet 116 of first cooling core 48 passes through the core and exits from outlet 122 and then is carried by conduit 124 to the inlet 126 of the second cooling core 50. The oil passes through the coils 128 of core 50, exits through outlet 130 and then is carried by conduit 132 to the second inlet 134 of thermostatic valve 120. The oil leaves thermostatic valve 120 passing from outlet 136 to conduit 138 which carries the oil back to compressor housing 34 where the oil is used to cool the compressor and provide sealing for operation of the compressor.

An alternate flow path for the oil in conduit 112 can be established by changing the setting of thermostatic valve 120. if this valve is set to allow communication between the first inlet and the outlet 136, the oil will bypass the cooling cores 48 and 50 and flow directly back to the compressor.

Conduit 108 connects siphon tube 104 to the inlet of the compressor to provide the source of lower pressure in order to siphon off the scavenged oil in'the bottom section 102 of the closed oil tight chamber.

OPERATION The construction of the invention set forth herein provides for efficient operation of the entire compressor system. Power for the compressor 22 is obtained from the vehicle engine 18 through the power take-off connection 20 on the engine and transmitted through the splined shaft 28 to the compressor rotor shaft 32. The rotary compressor shaft in turn provides power through splined shaft 40 to power the fan of the compressor cooler assembly. it should be apparent therefor that the fan of the compressor cooler assembly operates only when the rotary compressor is in operation. The compressor discharges through outlet 66 and conduit 68 into the inlet 72 of the air oil receiver-oil separator tank 70. Oil from the tank passes through conduit 112 to the T-fitting 114 which leads to either the inlet 116 of the first cooling core 48 or to the thermostatic valve 120.

If the oil is cold because the compressor has just started operation the thermostatic valve will position itself to communicate inlet 135 with outlet 136 thereby by-passing the cooling cores. As the compressor continues to operate the temperature of the oil rises and the thermostatic valve 120 will position itself to block off inlet 135 and to communicate inlet 134 with outlet 136 thereby establishing a How path from the air receiver-oil separator tank 70 through the first and second cooling cores and then back to the compressor.

The oil cooling assembly is constructed to provide maximum efficiency. The first and second cooling cores are arranged in series to provide for a counter current flow through the cores thereby providing maximum cooling efficiency by maintaining, as near as possible a constant temperature difference between the temperature of the oil to be cooled in the cores and the cooling air passing through the coils. To be specific, the air entering the first cooling core 48 has already been heated as it passed through the second cooling coil 50 and this warmed air cools the uncooled oil coming directly from the air receiver-oil separator tank. Similarly, oil entering the second cooling core 50 has been partially cooled in the first cooling core and is further cooled by the unheated air which is being drawn from the atmosphere through the second cooling core. It should be mentioned, of course, that two cooling cores are not critical to the function of the compressor system. A cooling system using one or three cooling cores would also be operable.

The positioning of the fan 54 to rotate in the horizontal plane and outside shroud 52 provides several advantages. Of primary importance is a considerable sav ing of space. The fan can now be mounted below the frame of the truck and does not take up any useful working space on the truck frame. In order for the horizontal fan to effectively draw air through the vertical first and second cooling cores it is necessary to surround the entire compressor cooler assembly with shroud 52. The shroud changes the direction of the air flow produced by the fan from horizontal as it passes the cooling cores to vertically downward as it approaches the fan 54. Because the fan rotates in a plane below the shroud, it imparts a large radial velocity component to the air it exhausts, thereby preventing a strong exhaust downdraft. Such downdrafts are undesirable since they cause large amounts of dust to be raised when the compressor system is working in certain environments. Additionally, by placing the cooling cores vertically between the rails 24 of the truck frame 12, the cores are provided maximum protection from damage due to road debris thrown up during over the road operation. Further, facing the cooling cores rearward prevents hot engine exhaust air from being drawn into the cooling cores by the fan, thereby eliminating the possible loss of cooling efficiency that would occur if the engine exhaust were drawn through the cooling cores.

Mention should be made of the advantages in construction of the air receiver-oil separator tank 70. Because the tank is of small diameter and mounted horizontally it can be easily positioned anywhere under the truck frame, for example under the running board 16 as shown in FIG. 1. However, because of the horizontal position and its small diameter the oil level in the tank is higher than the lowest point of the air-oil separator element. For this reason, the air oil separating element is placed within the oil tight container 84 within the tank and the inlet 100 to this oil tight container is at the top thereof to prevent any flow of accumulated oil into the oil separator filter element 92. Since the pressure in the air receiver-oil separator tank is approximately equal to the discharge pressure of the compressor any oil which has been separated by the oil separator element 92 and has accumulated in the bottom section of the oil tight chamber 84 can be easily removed by means of the siphon tube 104 which in turn is connected through conduit 108 to the inlet 64 of the compressor 22 where the oil is productively used.

What is claimed is: 1. A heat exchanger for vehicle mounted fluid operated devices, the vehicle having a horizontal main frame and a power supply drivingly connected to the fluid operated device, the heat exchanger comprising:

cooling core means mounted on the vehicle, said core means having an inlet and an outlet for transmitting liquid there-through to be cooled, and said core means also having passages therethrough for cooling air flow, the downstream side of said core means in the direction of cooling air flow defining a plane substantially perpendicular with respect to a plane defined by the vehicle main frame;

thermostatically controlled bypass valve means con nected between the inlet and outlet of said cooling core means for bypassing the liquid around said cooling core means;

fan means mounted on the vehicle and operatively associated with said cooling core means, said fan means having a fan drivingly connected to a vehicle power source and disposed to rotate in a plane which is substantially parallel to the plane.of the vehicle main frame, said fan means being offset along the vehicle frame with respect to said core means downstream in the direction of air flow whereby an extension of the plane in which said fan rotates in a substantially perpendicular relationship and whereby at least intersects the plane defined by said core means at least part of the air exhausted from said fan is dispersed horizontally; and

shroud means disposed about said cooling core means and communicating at one end with said fan means whereby operation of said fan means will effect air flow through said cooling core means.

2. The combination claimed in claim 8 wherein:

said cooling core means comprise first and second cooling cores, each of said first and second cores having an inlet and an outlet;

and further comprising conduit means communicating the outlet of said first cooling core means to the inlet of said second cooling core means to provide a series operational relationship between said cooling core means wherein the fluid to be cooled passes through said first and second cooling core means in sequence.

air flow thereby providing cross-counterflow cooling of the liquid.

4. The combination of claim 1 wherein:

the plane of rotation of the fan is below the plane of the vehicle main frame. 

1. A heat exchanger for vehicle mounted fluid operated devices, the vehicle having a horizontal main frame and a power supply drivingly connected to the fluid operated device, the heat exchanger comprising: cooling core means mounted on the vehicle, said core means having an inlet and an outlet for transmitting liquid therethrough to be cooled, and said core means also having passages therethrough for cooling air flow, the downstream side of said core means in the direction of cooling air flow defining a plane substantially perpendicular with respect to a plane defined by the vehicle main frame; thermostatically controlled bypass valve means connected between the inlet and outlet of said cooling core means for bypassing the liquid around said cooling core means; fan means mounted on the vehicle and operatively associated with said cooling core means, said fan means having a fan drivingly connected to a vehicle power source and disposed to rotate in a plane which is substantially parallel to the plane of the vehicle main frame, said fan means being offset along the vehicle frame with respect to said core means downstream in the direction of air flow whereby an extension of the plane in which said fan rotates in a substantially perpendicular relationship and whereby at least intersects the plane defined by said core means at least pArt of the air exhausted from said fan is dispersed horizontally; and shroud means disposed about said cooling core means and communicating at one end with said fan means whereby operation of said fan means will effect air flow through said cooling core means.
 2. The combination claimed in claim 8 wherein: said cooling core means comprise first and second cooling cores, each of said first and second cores having an inlet and an outlet; and further comprising conduit means communicating the outlet of said first cooling core means to the inlet of said second cooling core means to provide a series operational relationship between said cooling core means wherein the fluid to be cooled passes through said first and second cooling core means in sequence.
 3. The combination of claim 2 wherein: the fan means generates air flow in a given direction through the shroud means; and the first and second cooling cores of the cooling core means are disposed serially in the shroud means, the first cooling core being disposed downstream of the second cooling core in the direction of the air flow thereby providing cross-counterflow cooling of the liquid.
 4. The combination of claim 1 wherein: the plane of rotation of the fan is below the plane of the vehicle main frame. 